Cooperative OFDM-IM Relay Networks With Partial Relay Selection Under Imperfect CSI

Abstract

Abstract-In this work, we investigate the performance of cooperative orthogonal frequency division multiplexing with index modulation (OFDM-IM) with the low complexity greedy detection (GD). In particular, we propose a novel partial relay selection (PRS) scheme whose search criteria are designed to exploit the IM sub-carriers. To provide low-complexity receiver, we further examine the energy-sensing based GD design for the cooperative OFDM-IM. For the performance analysis we derive novel upper bound and approximate closed form solutions for both the average index error probability (IEP) and the average symbol error probability (SEP) over Nakagami-m fading channels with imperfect channel state information (CSI) at the relays and destination. Unlike the information theoretical works, in presence of positive detection error in the relays, the derived expressions provide a useful insight into the error performance of cooperative OFDM-IM under various fading conditions. The numerical and simulation results clearly present that the proposed scheme harmonizing partially selected relays and their IM sub-carriers with GD can outperform the benchmark schemes, under uncertain CSI, at reduced complexity.

Opportunistic Spectrum Sharing Based on OFDM With Index Modulation

“…Since k out of n subcarriers carry symbols from the PT and n − k from the ST, it follows that Pr(E) = k/n and Pr(Ē) = (n − k)/n. Hence, (23) reduces to (24), shown at the top of the next page, where C = ln(k) − ln(n − k) is a constant irrelevant to the detection. By resorting to (13)- (16), L(α) in (24) can be well approximated as…”

“…In [23], adaptive mapping schemes between IM bits and SAPs are presented for dual-hop OFDM-IM DF relaying networks. To enhance the system reliability, in [24]- [26], multiple relays with relay selection are employed for dual-hop OFDM-IM. In contrast to the dual-hop schemes in [23]- [26], multi-hop DF relaying is developed for OFDM-IM in [27], further enlarging the communication coverage.…”

Toward Spectral and Energy Efficient 5G Networks Using Relayed OFDM with Index Modulation

“…They adopt the cooperative dual-hop structure with relays in parallel and employ multi-carrier RS schemes. [11] assumes that only the CSI in the first hop is accessible at the source for RS purposes, so that a partial RS (PRS) scheme based on centralized control is formed. To be realistic, the channel estimation error is taken into consideration in this paper, which yields imperfect CSI for PRS.…”

Low-Complexity Detection for Index Modulation Multiple Access

“…Due to the high EE and anti-interference property, IM technique has been widely used in cognitive radio (CR) networks [14], cooperative networks [15], [16], and multiple access (MA) schemes [12], [17], [19]. In [14], the inactive subcarriers of orthogonal frequency division multiplexing with index modulation (OFDM-IM) are utilized to transmit the secondary user's signals in CR networks.…”